<?php

namespace Ruben\Aliyun;

class Oss
{
    private $accessKeyId;
    private $accessKeySecret;
    private $endpoint;
    private $defaultBucket;
    private $cdn;

    public function __construct($config)
    {
        $this->accessKeyId = $config['access_key_id'];
        $this->accessKeySecret = $config['access_key_secret'];
        $this->endpoint = $config['endpoint'];
        $this->defaultBucket = $config['bucket'];
        $this->cdn = $config['cdn'];
    }


    public function prepareUpload()
    {
        function gmt_iso8601($time) {
            $dtStr = date("c", $time);
            $mydatetime = new \DateTime($dtStr);
            $expiration = $mydatetime->format(\DateTime::ISO8601);
            $pos = strpos($expiration, '+');
            $expiration = substr($expiration, 0, $pos);
            return $expiration."Z";
        }
    
        $id = $this->accessKeyId;
        $key = $this->accessKeySecret;
        $host = $this->cdn;
        $callbackUrl = "http://oss-demo.aliyuncs.com:23450";
    
        $callback_param = array('callbackUrl'=>$callbackUrl, 
                     'callbackBody'=>'filename=${object}&size=${size}&mimeType=${mimeType}&height=${imageInfo.height}&width=${imageInfo.width}', 
                     'callbackBodyType'=>"application/x-www-form-urlencoded");
        $callback_string = json_encode($callback_param);
    
        $base64_callback_body = base64_encode($callback_string);
        $now = time();
        $expire = 30; //设置该policy超时时间是10s. 即这个policy过了这个有效时间，将不能访问
        $end = $now + $expire;
        $expiration = gmt_iso8601($end);
    
        $dir = 'user-dir/';
    
        //最大文件大小.用户可以自己设置
        $condition = array(0=>'content-length-range', 1=>0, 2=>1048576000);
        $conditions[] = $condition; 
    
        //表示用户上传的数据,必须是以$dir开始, 不然上传会失败,这一步不是必须项,只是为了安全起见,防止用户通过policy上传到别人的目录
        $start = array(0=>'starts-with', 1=>'$key', 2=>$dir);
        $conditions[] = $start; 
    
    
        $arr = array('expiration'=>$expiration,'conditions'=>$conditions);
        //echo json_encode($arr);
        //return;
        $policy = json_encode($arr);
        $base64_policy = base64_encode($policy);
        $string_to_sign = $base64_policy;
        $signature = base64_encode(hash_hmac('sha1', $string_to_sign, $key, true));
    
        $response = array();
        $response['accessid'] = $id;
        $response['host'] = $host;
        $response['policy'] = $base64_policy;
        $response['signature'] = $signature;
        $response['expire'] = $end;
        $response['callback'] = $base64_callback_body;
        //这个参数是设置用户上传指定的前缀
        $response['dir'] = $dir;
        echo json_encode($response);
    }

    
}
